comparison hmm/hmm.c @ 30:a251fb0de594

* Make MFCC able to accept already-FFT'd input, and simplify API a bit
* Add log power value to MFCC, restore windowing, and avoid some heap allocs
* In HMM, bail out of iteration if loglik hits NaN

 	
 	double thresh = 0.0001;
 	int niter = 50;	
 	int iter = 0;
 	double loglik1, loglik2;
-	while(iter < niter && !(iter > 1 && (loglik - loglik1) < thresh * (loglik1 - loglik2)))	
+	int foundnan = 0;
+
+	while (iter < niter && !foundnan && !(iter > 1 && (loglik - loglik1) < thresh * (loglik1 - loglik2)))	
 	{
 		++iter;
 		
 		fprintf(stderr, "calculating obsprobs...\n");
 		fflush(stderr);

 		forward_backwards(xi, gamma, &loglik, &loglik1, &loglik2, iter, N, T, p0, a, b);
 		
 		fprintf(stderr, "iteration %d: loglik = %f\n", iter, loglik);		
 		fprintf(stderr, "re-estimation...\n");
 		fflush(stderr);
+
+		if (isnan(loglik)) {
+		    foundnan = 1;
+		    continue;
+		}
 		
 		baum_welch(p0, a, mu, cov, N, T, L, x, xi, gamma);
 			
 		/*
 		printf("a:\n");

 		}
 		//double s = 0;
 		for (j = 0; j < N; j++)
 		{
 			a[i][j] = 0;
+			if (sum_gamma[i] == 0.) continue;
 			for (t = 0; t < T-1; t++)
 				a[i][j] += xi[t][i][j];
 			//s += a[i][j];
 			a[i][j] /= sum_gamma[i];	
 		}